See math on page 42. Do the math yourself if you don't believe me, but please don't make oversimplified, ignorant comments without at least reading the 3 hours of writing and statistics I did to prove otherwise. Diamond has an average of 2.85 blue cards in an opener, and Chrome has 3.22, and 45% of the time they picth one. Hardly a 2 blue cards vs 3 blue cards 'OMG my deck runs 3-4 more threats in a deck of 60!' Come on Taco, you've been here long enough - I didn't expect such a blindly biased comment from you.
/subject
@ replacement for drakes: looter/mulldrifter/TfK will likely dig you into your better, (more availible such as efreet, faeries, and mage) threats, and will decrease the number of inferior spells you play in lieu of Drake. (aka a 3/3 for 3U) I would recommend a few more lands and 3-5 of the above cards. More professionally, I would simply recommend you suck it up and buy 4 drakes, as it is the best beater in the deck, and I am not alone in believing if you can't afford to play a deck, play a cheaper one optimally rather than playing (this) deck with sub-optimal cards. See 'budget' threads for more info.
tl;dr: you wouldn't run thresh with out goyf, you shouldnt run FS without drakes.

